Shoes that tone your hamstrings while you walk sound kinda cool until you stop to realize that, um, walking tones your hamstrings while you walk. On it’s own, you know? Makers of toning shoes, of course, claim the shoes provide an extra toning umph that plain old walking can’t—but the Federal Trade Commission isn’t buying it. Now the agency is making toning shoe manufacturer Reebok pay up for making such unsubstantiated claims.

In commercials released last year for Reebok’s EasyTone shoes, the company claimed EasyTones (which sell for $80-$100 per pair) can “tone your hamstrings, calves and butt up to 28% more.” More than what? The commercials don’t say, but anyone can infer that it means ‘more than walking without these shoes.’ How did they test this theory? Well, apparently, they didn’t (or at least not in any way that holds up to legal scrutiny).

The FTC filed a complaint against Reebok, charging the company with making false claims by stating in print, online and TV advertisements that EasyTone and RunTone shoes strengthen and tone muscles more than regular shoes. David Vladeck, director of the FTC’s Bureau of Consumer Protection, said “The FTC wants national advertisers to understand that they must exercise some responsibility and ensure that their claims for fitness gear are supported by sound science.”

Reebok agreed to a $25 million settlement, which will go toward providing refunds to consumers who bought EasyTone or RunTone shoes (to apply for a refund, go here).

Toning shoes might be a bad buy for reasons other than not living up to claims. Ads claim the shoes function on pockets of moving air in the soles that create ‘micro instability,’ for extra toning and strengthening. But while instability is beneficial during workouts, it can be dangerous to go around being literally unstable all the time. Earlier this year, Blisstree talked to personal trainer Andrew Sutherland about toning shoes’ safety; he said the shoes could cause injuries similar to ones sustained from high-heels and stilettos.

Being unstable for long periods of time “causes injuries, bad hip posture and takes toes out of the equation, (which are the) main receptors for balance and other important nervous system information that is constantly relayed to the brain,” Sutherland said. “Constantly wearing the shoes can increase the chance of rolling your ankle or falling over. By causing bad hip posture, they can also lead to muscle tension, tears, and lower back pain.”